"Thus to the plain man there may be no metaphor in Aristotle's "substance", Descartes' "machine of nature," Newtonian "force" and "attraction," Thomas Young's "kinetic energy" and Michelangelo's figure of Leda. Placed in their customary contexts these present nothing to him but the face of literal truth. To the initiated, however, who are aware of the "gross original" senses as well as the now literal senses , they may become metaphors. There are no metaphors per se...."